Narrow bandgap ii-vi semiconductors: growth

Abstract

The field of narrow bandgap II-VI semiconductors is dominated by the compound Hg1−xCdxTe (MCTmercury cadmium telluride (MCT)), although some Hg-based alternatives to this ternary have also been suggested. The fact that MCT is still the preeminent infrared (IRinfrared (IR)) material stems, in part, from the fact that by varying the x value material can be made to cover all the IR regions of interest. In addition, the direct band transitions are responsible for large values of absorption coefficients, allowing quantum efficiencies to approach 100%. Long minority carrier lifetimes result in low thermal noise allowing high-performance detectors to be made at the highest operating temperatures of comparable wavelengths. This chapter covers the growth of MCT by various bulk growth techniques, used mainly for first-generation infrared detectors; by liquid phase epitaxy, used mainly for second-generation infrared detectors; and by metal-organic vapor phase and molecular beam epitaxies, used mainly for third-generation infrared detectors.